Spark plug cover



FIG. 1 is a front top and side perspective view of a spark plug cover showing our new design. The broken line showing of the spark plug is included for the purpose of illustrating environmental elements only and forms no part of the claimed design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side plan view thereof; and,

FIG. 4 is a bottom plan view thereof. 

The ornamental design for a spark plug cover, as shown and described. 